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If Trump wants to use nuclear weapons, whether it’s ‘legal’ won’t matter

The Senate Foreign Relations Committee examines the president’s authority to order a nuclear strike amid rising tensions with North Korea. (Video: Jordan Frasier/The Washington Post)

No national decision is as consequential, irreversible and fateful as the decision to use nuclear weapons. In the United States the president, and only the president, has the authority to order the unleashing of nuclear weapons. This power is not given by the Constitution, nor any specific law. It results from a series of Cold War-era decisions made secretly by the executive branch and the U.S. military.

Which means recent statements by current and former four-star commanders of the Strategic Command — the branch of the military that would launch nuclear weapons were such a thing to happen — that the military would only carry out “legal” presidential orders to use nukes shouldn’t be particularly reassuring.

News coverage of these comments seemed to convey the idea that the military could be a fail-safe to prevent a nuclear launch, but the opposite remains true. Instead, they revealed what many of us outside the system have suspected for a long time: There are no “checks and balances” on nuclear launch decisions in any formal sense. There is no need for congressional authorization; there is no “two-man rule” for the decision to use the bomb; and although the process for initiating a nuclear attack spells out the need for “consultation” with officials such as the secretary of defense, they have no power to veto the order, and ultimately, their consent is not required. If President Trump wants to use one of the thousands of nuclear weapons in the U.S. military’s arsenal, the chance of anyone stopping him appears to be very low.

No one can stop President Trump from using nuclear weapons. That’s by design.

Both Gen. John Hyten, the head of U.S. Strategic Command, and retired Gen. C. Robert Kehler, the commander from 2011 to 2013, have spoken recently about not following “illegal” orders to use nukes. Speaking at the Halifax International Security Forum last weekend, Hyten said he’d push back: “I provide advice to the president, he will tell me what to do,” he said. “And if it’s illegal, guess what’s going to happen? I’m going to say, ‘Mr. President, that’s illegal.’ And guess what he’s going to do? He’s going to say, ‘What would be legal?’ And we’ll come up with options, with a mix of capabilities to respond to whatever the situation is, and that’s the way it works. It’s not that complicated.”

Hyten meant this to calm alarm, but it shouldn’t. If anything, it reaffirms our belief that “legality” is the wrong issue altogether. For a general to affirm that he would not obey an “illegal” order is not a strong stance — it’s a simple refusal to willingly commit a war crime, the bare minimum we should expect from a high-ranking American officer. The rest of Hyten’s statement makes clear that he sees his role as a bargainer who would advise the president how to accomplish his desired ends by facilitating a legal alternative.

In other words, this is not a principled form of resistance. It is, in the end, “not that complicated”: The president, one way or another, will probably get what he wants.

Hyten’s remarks came just a few weeks after Sen. Bob Corker (R-Tenn.), chair of the Senate Committee on Foreign Relations, held the first hearings since 1976 on presidential nuclear authority. The hearings in the 1970s featured the looming specter of Richard Nixon as the “mad man” to be feared. The recent hearings took place amid concerns about trusting Trump with the most awesome presidential decision: to release the ultimate “fire and fury.”

Kehler attempted to reassure senators that rash use — or abuse — of nuclear weapons was unlikely under the current system. An unexpected order from the president, he explained, would end up on his desk, and he wouldn’t just execute it unthinkingly like a robot. Rather, he and his legal staff would evaluate it as they would any other order. And if it was an “illegal” order, he wouldn’t follow it.

But what exactly would constitute an “illegal” order? No U.S. laws give guidance on nuclear attacks. Kehler referred instead to the Law of Armed Conflict, the directives created by the Pentagon to make sure American military actions are in line with the international law and treaties, like the Geneva Conventions, that the United States considers binding. The legality Kehler referred to related to issues such as military necessity, discrimination, and proportionality: “just war” concepts that codified into international treatises that, taken together, rule out wanton destruction for its own sake.

Compliance with the Law of Armed Conflict is in itself a good thing — if, again, a low bar. But how would that apply in anything but the most insane scenarios? And who would or could make that final determination? What if the White House legal staff came up with their own arguments in favor of a rash attack? The past 50 years of American warfare has shown that presidents and their advisers have been able to come up with “just war” arguments for every military engagement, no matter how stretched in retrospect. Using a nuclear weapon on Pyongyang, for example, could be theoretically justified by arguing that it would be a legitimate military target (much of North Korea’s command and control infrastructure and leadership is probably located there) and that not doing it would be more consequential (in the same way that the use of atomic bombs on Hiroshima and Nagasaki in 1945 was buttressed by arguments that ending World War II without a ground invasion of Japan saved lives). Would this reasoning stand up in a court of law? Would it ever come to a court of law? The lawyers making it would know it would never have to: The United States has a weak record on prosecuting its own service members for doing what they could argue they thought was right, whatever the consequences.

I’m a nuclear weapons expert. Trump’s presidency is my personal nightmare.

Under questioning, Kehler admitted that what and who would define and ascertain that legality was indeed obscure or unknown in situations that did not follow a preconceived “playbook” (such as a massive incoming nuclear attack from Russia). And he noted that the U.S. government does not view the use of nuclear weapons as inherently illegal or rule out first use; it depends on the situation.

So how would the vetting of legality that Kehler proposed be done? And what would happen if he did refuse a direct order as “illegal,” something that appears unprecedented in the history of American generals? Kehler responded uneasily when asked: “Other than to state their view about the legality of the move, uh, the president retains constitutionality authority to order some military action. The military … [uncomfortable smile] you would be in a very interesting constitutional situation, I believe.”

The hearings were marked by several of these uncomfortable moments and eliding euphemisms. A listener might be forgiven for forgetting that the hundreds of thousands — if not millions — of lives might hang on the resolution to the “very interesting constitutional situation.” When asked explicitly by Sen. Ron Johnson (R-Wis.) how he would have responded to what he thought was an illegal order to use nuclear weapons by the president, Kehler replied with a nervous laugh: “I would have said, ‘I have a question about this,’ and I would have said, ‘I am not ready to proceed.’ ”

What would happen next, Johnson asked? “Well … as I say, I don’t know, exactly,” Kehler said. “Fortunately, we’ve never … these are all hypothetical scenarios … this is the human factor in our system. The human factor then kicks in … there’s a human element to this.”


An uncomfortable sense of profound uncertainty permeates these sorts of questions. It permeated the hearings of the 1970s, as well. The military side of the U.S. nuclear arsenal has been set up to enact the will of the civilian government in the face of massive external threats. But if the civilian government is itself unreliable or unwise, that unmoors the entire system, and goes entirely counter to the assumptions that were built into the system during the Cold War.

This new focus on “legality” as the key issue is a red herring. The legal scenario contemplated here is not a court of law (with adversarial lawyers and a judge, much less a jury), but a rushed, in-house assessment of whether a military action can be narrowly construed as justified under the often nebulous laws of war or interpretations of executive powers under the Constitution.

What most worries people who study this issue is not a “mad president” who impulsively decides to begin World War III. We are worried about real-world scenarios in which the first use of a few nuclear weapons might look appealing, or even militarily tempting. For instance, a president might be tempted to use nuclear weapons to destroy an underground bunker or hardened facility (hard to do with conventional weapons, easy to do with nuclear ones), or to attack areas where the precise target is not known (such as mobile missiles hidden in forests). These are the sorts of situations that U.S. security advisers and presidents contemplated in previous wars, even in previous crises.

As scholar Nina Tannenwald makes clear in “The Nuclear Taboo,” the idea that nuclear weapons must not be used in war was not obvious for most of the 20th century; again and again, presidents were presented with “opportunities” and “options” to use them, especially very small nuclear weapons that blurred the line between conventional and nuclear warfare. In all these situations, the president did indeed serve as the final civilian “check.” In retrospect, that the United States has not used nuclear weapons since 1945 has been a boon to our security and the world’s: It has helped maintain the idea that nuclear weapons are not appropriate for use. The United States, with its “easy targets” of highly centralized cities and military bases, benefits from this taboo as much, if not more, as any nation.

Why Kim Jong Un wouldn’t be irrational to use a nuclear bomb first

Near the end of last week’s hearing, Sen. Jeanne Shaheen (D-N.H.) asked the hard but necessary question: Should or could anything be done? Witnesses shied away from proposing anything. All warned that congressional remedies should not be rushed into, that trying to fix a complex, extremely sensitive and highly classified system would be most difficult. Which is fair — these are complex issues, and we should be wary of a quick fix that ultimately would embolden enemies or weaken U.S. nuclear deterrence.

Nevertheless, it is high time to reexamine these issues. This is not an abstract and “very interesting” hypothetical question; it is a strikingly real possibility. Backroom discussions by lawyers working for the military or the White House are not adequate “checks” on the actions of a rash president, especially if they see their primary aim as carrying out the will of the commander in chief. It is time to think the truly unthinkable: not that a hostile power might bring the United States reluctantly toward the use of nuclear weapons again, but that the president himself may do so.

With virtually every other aspect of the handling of our nuclear weapons, there is a “two-man rule,” requiring the cooperation of two people to do anything that could be potentially dangerous. One person can be unreliable, but pairs tend to reinforce one another. It is not so absurd to contemplate extending this principle to the top of the nuclear chain of command, nor to contemplate a system of checks and balances that ensured that “could this be construed as legal?” was not the only question being asked before nuclear weapons are launched. And Congress should take a role in defining what use of nuclear weapons is or isn’t against the law. Because if not Congress, who else can do it? Who will?

Read more:

Presidents have too much power over U.S. nukes. Especially President Trump.

Trump likes to be ‘unpredictable.’ That won’t work so well in diplomacy.

How President Trump could tweet his way into nuclear war with North Korea